The present invention relates generally to welding-type systems and, more particularly, to an apparatus that provides welding-type power to a MIG welding gun while also providing a quick and easy means for supplying welding-type power to a spoolgun.
There are many welding-type systems used for a variety of applications. The term “welding-type systems”, as used herein, includes arc welding systems, plasma cutting systems, and induction heating systems. Accordingly, the term “welding-type power”, as used herein, may refer to welding, plasma cutting, or induction heating power. One primary component of all welding-type systems is a power supply that delivers conditioned welding-type power to perform a specific welding-type process.
Some welding-type applications, such as steel arc welding, utilize a motor driven wire feeder, or wire drive, that delivers a consumable wire electrode to a welding gun, or torch, to perform a desired welding-type process, such as MIG welding. One common type of wire drive is a voltage sensing wire drive. Voltage sensing wire drives are typically connected, via a cable, to the positive terminal of a welding-type power supply. The wire drive is further coupled to the consumable wire electrode. The negative terminal of the power supply is connected to a workpiece such that when the positive wire electrode is close enough to the negative work piece to create an arc, a desired welding process occurs. Generally, voltage sensing wire drives become active when the voltage and/or current provided by an associated power supply increases above a threshold value. In this regard, the wire drive does not typically receive control signals or communicate with the power supply.
In other welding-type applications, for example, MIG welding with a consumable aluminum wire electrode, the standard wire drive may not be suitable. For instance, when MIG welding with aluminum wire, special equipment adapted specifically to handle the softer wire must be used. Aluminum wire electrodes can easily be damaged by equipment otherwise acceptable for steel wire electrodes.
One type of equipment suitable for aluminum welding is known as a spoolgun. The spoolgun is a self-contained welding gun equipped to feed a soft wire electrode from a small spool mounted directly on the gun. The distance from the wire to the contact tip is very short, usually less than twelve inches and therefore is better able to feed the soft aluminum wire electrode without problems. A spoolgun power supply cable, typically up to 50 feet in length, is run between the welding power supply and the spoolgun.
Users that switch frequently between steel and aluminum welding often find it convenient and cost-effective to purchase and use a single welding machine that is able to drive both a spool gun and a standard MIG gun. Some existing welding machines are configured such that a MIG gun and a spoolgun may be connected to the welding machine at the same time.
Referring now to FIG. 1, one such prior art welding machine 10 is shown. The welding machine 10 is powered by a switched or inverter-based power supply 12 contained within a housing 14. A pair of welding-power output terminals 16, 18 extend from the housing 14. The welding machine 10 further includes a power input connection (not shown) that receives AC power, such as that received from a standard power receptacle. As is known in the art, the supply power is rectified and conditioned, thereby converting the incoming AC power to a DC welding-type power.
As shown, the welding machine 10 is connected to a standard MIG welding gun, or torch, 20 that delivers a consumable wire electrode 22 to effectuate a welding-type operation. The wire electrode 22 is electrically connected to the positive welding power terminal 16, as described in greater detail below, while a work piece 24, upon which a welding-type operation will occur, is electrically connected to the negative welding power output terminal 18 via a clamp 40 and a grounding cable 38 extending therebetween.
When the positively charged wire electrode 22 either makes direct contact with the negatively charged workpiece 24 or the gap therebetween is sufficiently narrow, an arc is created between the wire 22 and workpiece 24, resulting in a completed circuit and causing a welding-type process to occur. In one welding-type process, i.e., arc welding, the resulting electrical current and voltage cause the wire electrode 22 and a portion of the workpiece 24 to become superheated and melt. The melted electrode 22 and workpiece 24 mix together and then cool to become permanently bonded together.
The welding machine 10 is further comprised of an automatic wire drive 26 that feeds the consumable wire electrode 22 from a supply spool 28 to the welding gun 20 when a trigger 21 is depressed. In the illustrated embodiment, the welding power output terminals 16, 18 and wire drive 26 are situated in close proximity to each other within a compartment 30 of the welding machine 10. However, other configurations exist where the wire drive 26 is located external to the welding machine 10.
The wire drive 26 receives the welding-type power via an electrically conducting cable 32 connected between the positive terminal 16 and the wire drive 26. The consumable wire electrode 22 becomes energized when passing through a power pin 31 (see FIG. 2) that is electrically coupled to the wire drive 26. The wire electrode 22 is then run inside a shielding gas hose 33 to the MIG gun 20. The hose 33, electrode 22 and a control cable 34 may be integrated into a single sheathed assembly 36 extending between the welding machine 10 and the gun 20. The grounding cable 38 is connected to the workpiece 24 via the grounding clamp 40 and the negative welding power terminal 18 via an electrical connector to provide a return path for the electrical current.
Still referring to FIG. 1, a spoolgun 42 may be connected to the welding machine 10 at the same time as the MIG gun 20. Connections between the spoolgun 42 and the welding machine 10 include a separate control cable 44, shielding gas hose 46, and power supply cable 48. Because the spoolgun 42 does not use the consumable wire electrode 22 supplied by wire drive 26, the separate power supply cable 48 is needed to supply the welding-type power from the power supply 12. In operation, a separate spool of consumable wire electrode (not shown) stored within the spoolgun 42 is energized and supplied to the workpiece 24 to effectuate a welding-type process.
To connect the spoolgun 42 to the power supply 12, the positive welding power terminal 16 must be accessed by opening the welding machine 10 to reveal the compartment 30. A wrench or similar tool is typically used to loosen a nut 50 tightened onto the terminal 16. One end of the spoolgun power cable 48, typically provided with a suitable electrical connector 17 is then fixedly fastened to the terminal 16 by tightening the nut 50 against the connector 17 as shown. The aforementioned cable 32 for the wire drive 26 is also secured to the positive output terminal 16 in a similar manner.
To disconnect the spoolgun 42 from the welding machine 10, the aforementioned process is essentially reversed. A tool is needed to loosen the nut 50 from the terminal 16 and as a result it is common practice to leave the spoolgun 42 connected to the welding machine 10 with the power cable 48 coiled up, even when not needed.
It is labor intensive and time consuming to add or remove a spoolgun 42 in this manner. Further, repeated tightening and loosening of the nut 50 may cause operational problems. For example, the nut 50 may not be tightened sufficiently and work itself loose over time. Still further, tools, such as wrenches and the like, are easily misplaced or lost resulting in time wasted while looking for a suitable tool to loosen the nut 50 from the power terminal 16. For these reasons, repeatedly connecting and disconnecting the spoolgun power supply cable 48 directly to the positive welding terminal 16 is not a desirable practice in the welding industry. Instead, many users leave the spoolgun 42 semi-permanently connected to the welding machine 10, even when not planning to use it, rather than disconnecting the spoolgun 42.
Even this practice has drawbacks, however. When a spoolgun 42 is left connected to a welding machine 10, the spoolgun power supply cable 48 is typically coiled up and stored, along with the spoolgun 42 alongside the exterior of the welding machine 10. The spoolgun 42 and power supply cable 48 are thus exposed and unprotected against environmental conditions, accidental contact with other equipment, or simply being dropped on the ground.
Therefore, a need exists for an improved apparatus and method for quickly and easily connecting and disconnecting a spoolgun to a standard welding machine without the need for tools.
Accordingly, attempts have been made to design various quick connect and release cables for spool guns. Such cables provide a quick and easy way to connect and/or disconnect a spoolgun and its associated power supply cable and gas hose. A number of prior art systems require special connectors and unique cable assemblies that cannot be used on existing welding machines.
One such prior art quick release connector mechanism is disclosed in U.S. Pat. No. 7,208,699. However, one drawback to this and similar prior art devices is that these mechanisms will not work on existing spoolguns or welding machines without substantial modifications, if at all.
Therefore, it would be desirable to have a quick-connect device for a welding machine such that a spoolgun or other welding implement may be added or removed from a welding machine without the need for tools and without the need to retrofit an existing welding machine.